Postretirement Benefit Plans - Accumulated Other Comprehensive Income (Loss) Related to Qualified Defined Benefit Pension and Retiree Medical and Life Insurance Plans (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Qualified Defined Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (losses) gains	$ (10,469)	$ (10,999)
Prior service (costs) credits	(164)	(15)
Total	(10,633)	(11,014)
Estimated tax	2,255	2,339
Net amount recognized in accumulated other comprehensive (loss)	(8,378)	(8,675)
Retiree Medical and Life Insurance Plans
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (losses) gains	518	416
Prior service (costs) credits	2	(2)
Total	520	414
Estimated tax	(110)	(87)
Net amount recognized in accumulated other comprehensive (loss)	$ 410	$ 327

Accumulated Other Comprehensive Income (Loss), Defined Benefit Plan, Tax

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- Definition

Amount, after tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

+ References

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-Name Accounting Standards Codification
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-Topic 715
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-Name Accounting Standards Codification
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-Paragraph 1
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- Definition

Amount, before tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

+ References

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Amount, before tax, of accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount, before tax, of accumulated other comprehensive (income) loss for cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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